Containment vessel vacuum relief assembly with tamper deterrent

ABSTRACT

A vacuum relief assembly for a containment vessel. The vacuum relief assembly includes a normally closed pressure activated valve assembly that selectively permits flow into the containment vessel from the atmosphere through an interior passage. The valve body includes inlet opening into the interior passage. It also includes a torque acceptance portion to permit connection of the valve assembly to a vessel. A tamper resistant cap is secured in overlying relation to the inlet opening and the torque acceptance portion. The cap is secured with mechanism that provides indicia of tampering.

TECHNICAL FIELD

The present invention is directed generally to vacuum relief assemblies for containment vessels. More particularly, it is directed to vacuum relief assemblies which deter tampering to gain unauthorized access into the vessel.

BACKGROUND OF THE INVENTION

Containment vessels may be used to store and/or carry a wide range of materials including chemicals, foodstuffs and the like. Common forms of containment vessels are railway tank cars or highway tank trucks. Such vessels are generally operated at an interior pressure that is neutral or slightly positive relative to outside atmospheric pressure. These vessels, however, are typically not well suited to withstand vacuum conditions wherein the pressure at the interior of the tank car drops significantly below exterior atmospheric pressure.

To address the avoidance of vacuum conditions within a tank car or other containment vessel, it is generally known to utilize vacuum relief valves that open selectively to deliver air from the atmosphere into the interior of the vessel when the internal pressure drops below a predetermined level. This introduction of air is carried out by opening a normally closed flow path between the atmosphere and the vessel interior. Upon opening the flow path, air is pulled from the atmosphere into the vessel interior until the pressure differential is substantially eliminated. The flow path is thereafter closed until vacuum conditions reoccur. An example of such a vacuum relief valve is a valve available from Salco Products, Inc., Lemont, Ill.

While such systems are quite effective, the device presents an opportunity for intentional tampering to gain unauthorized access to the vessel interior.

BRIEF SUMMARY OF THE INVENTION

A vacuum relief assembly for a containment vessel is provided. The vacuum relief assembly includes a pressure activated vacuum relief valve with a torque acceptance portion employed to affix the valve to the vessel. The valve includes a valve body defining a flow path to the interior of the valve body. The valve is adapted to be selectively opened to fluid communication from the atmosphere to the interior portion of a containment vessel. A cap is secured to the body and overlies the inlet end of the flow path to prevent access. The cap includes side walls overlying the torque acceptance portion of the valve body to prevent access. Effort to remove the cap provides visual indicia of tampering.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings illustrate exemplary embodiments and constructions of the present invention and, together with the general description given above and the detailed description set forth below, serve to explain the principles of the invention wherein:

FIG. 1 illustrates an exemplary containment vessel in the form of a railroad tank car including a vacuum relief assembly;

FIG. 2 is an exploded view of an exemplary vacuum relief assembly valve body illustrating an embodiment according to the present invention;

FIG. 3 is a cross-sectional view of the interior of the valve body of FIG. 2 taken generally along line 3-3 of FIG. 2; and

FIG. 4 is a sectional plan view of a vacuum relief assembly embodying principles of the present invention in assembled condition inserted within a flange plate of a containment vessel.

FIG. 5 is a fragmentary sectional view of an alternative arrangement embodying the principles of the present invention.

DETAILED DESCRIPTION OF ILLUSTRATED EMBODIMENTS

Reference will now be made to the drawings wherein, to the extent possible, like reference numerals are used to designate like elements throughout the various views.

FIG. 1 illustrates a containment vessel in the form of an exemplary railroad tank car 10. As will be appreciated, the tank car 10 includes a containment shell 12 which is typically formed from steel or other structural material defining an interior storage chamber adapted to hold a cargo which may be liquid or particulate solids. The interior storage chamber may be accessed via a hatch structure 14 which may be opened and closed by an operator. During transportation of the tank car 10, the hatch structure 14 normally remains closed and locked to prevent contamination or spillage of the cargo.

The illustrated tank car 10 includes a flange plate 20 disposed across a surface of the containment shell 12. It includes a threaded opening into the interior chamber of the shell 12 adapted to accept a vacuum relief assembly 22.

The vacuum relief assembly 22 defines a flow path to allow air into the interior storage chamber in the event that vacuum conditions develop within the interior storage chamber. The path is otherwise closed when atmospheric pressure and the pressure within the chamber are balanced.

In the illustrated arrangement, the vacuum relief assembly 22 is secured to the flange plate 20 within the threaded opening. It is, however, contemplated that the vacuum relief assembly 22 may be disposed at an opening within the containment shell 12 or at the hatch structure 14 or other suitable portion of the tank car 10.

One exemplary construction of the vacuum relief assembly 22 is illustrated in FIGS. 2-4. The vacuum relief assembly 22 includes a hollow valve body 26 formed from steel or other metal. Valve body includes interior wall surface 27 that defines an open interior passage 28. The lowermost end of the valve body defines an outlet opening 30 surrounded by conical valve seat 31.

The valve body 26 includes a lower end defining a securement portion. It includes threads 29 adapted to engage threads in the opening within the flange plate 20. The threads are illustrated as pipe threads (NPT) a common method of attachment. It is contemplated, however, that valve body 26 may include a bolt flange rather than a threaded end. In that instance the flange plate 20 would include a hole, opening into the interior of the shell 12 of vessel 10 and threaded studs arranged about the hole to receive the bolt flange of the valve body 26.

In order to facilitate threaded engagement, the illustrated valve body 26 includes a hexagonally shaped flange 32 to accept a wrench. It would, however, have any other commonly used torque-acceptance configuration to receive a tool to tighten or loosen the valve body 26 relative to the flange plate 20.

As shown, a shoulder surface 36 faces upwardly away from flange 32. As best illustrated in FIG. 2, generally annular upper sidewall 34 extends upwardly from the shoulder surface 36 to a top edge surface 38.

In the illustrated construction, mounting posts 46 project upwardly from the upper edge surface 38 of the upper sidewall 34 and define the upper end of the valve body 26. Each has a top surface 47 provided with a threaded hole 48. The mounting posts 46 are preferably integral with the upper sidewall 34 although they may be formed separately if desired. The outboard surface of the mounting posts 46 is preferably generally aligned with the outer surface of the annular upper sidewall 34. The arcuate open spaces 42 between posts 46 define an inlet opening 40 with access to the atmosphere surrounding the vacuum relief assembly 22. The flow inlet opening 40 provides continuously open fluid communication path between the atmosphere and interior passage 28 of the valve body 26.

As best understood through reference to FIGS. 3 and 4, in the illustrated arrangement, the valve body 26 includes an annular valve guide 70 defining a valve guide surface 72. It also defines a spring support shoulder 74. Valve guide 70 is supported by radial webs 75 projecting inwardly from the interior wall 27 of the valve body 26 that defines passage 28. The webs 75 are spaced around the interior of the valve body 26 such that air can flow through the passage from the inlet opening 40 defined by the open spaces between mounting posts 46 through passage 28 and through the outlet defined by conical valve seat 31.

As illustrated in FIG. 4, the interior passage 28 is normally sealed against fluid communication with the interior of the tank car 10 by a movable valve 60. Valve 60 includes a head 61 that defines a conical seat surface 65 that seals against conical valve seat 31 on valve body 26 to close passage 28 against flow. A face surface 62 is exposed to the interior of containment shell 12.

Head 61 is connected to an elongate valve stem 64 extending axially of the interior passage 28 and slidable within guide surface 72. Its free end is threaded and receives a nut 67 that limits the position of a valve bushing 68 disposed at an upper end of the stem 64 remote from the valve head 61. A compression spring member 69 is held in a compressed condition between the valve bushing 68 and the spring support shoulder 74. As will be appreciated, such an arrangement continuously urges the valve stem 64 and head 61 upwardly to a sealing position with conical seat 65 sealed against conical seat 31 of body 26 as shown. In this normally closed position, fluid communication through outlet opening 30 is blocked between the interior passage 28 and the interior of the tank car 10.

In the event that the valve 60 is subjected to a downward force due to the occurrence of a negative pressure at the face surface 62, the valve 60 overcomes the biasing force provided by the spring member 69 and moves away from the illustrated sealing relation with seat 31 thereby establishing fluid communication between the interior of the tank car 10 and the interior passage 28 of valve body 26. Since the interior passage 28 is open to the atmosphere at communication paths defined by inlet opening 40, fluid communication is established between the interior of the tank car 10 and the atmosphere with the interior passage 28 acting as an intermediate conduit.

Accordingly, due to a low pressure condition within the tank car 10, air flows from the atmosphere, through the interior passage 28 and into the interior of the tank car 10. This flow path remains open until the vacuum condition within the tank car is reduced to a level permitting the valve 60 to return to the normally closed and sealed condition.

In the illustrated arrangement best seen in FIGS. 2 and 4, a cap 52 is secured across the mounting posts 46. As shown, the cap 52 has a circular top wall 53 with an interior generally planar surface 54. A pair of holes 56 extend through top wall 53 aligned with threaded holes 48. Cap 52 has a vertical cylindrical side wall 58 having a length that exceeds the length of the mounting posts 46, the upper wall portion 34 and the hexagonally shaped flange 32. Wall 58 of cap 52 has an inner diameter exceeding the maximum dimension of the valve body at the hexagonally shaped flange 32 (across the points of the hexagonally shaped flange 32).

In the illustrated arrangement, the cap 52 is secured to the mounting posts 46 by fastener members in the form of attachment bolts 59 extending through holes 56 in top wall 53 and into threaded holes 48 in top surfaces 47 of the mounting posts 46. The top wall 53 of the cap 52 is held substantially parallel to the shoulder surface 36 with the cylindrical side wall 58 outwardly beyond the outer surface of the mounting posts 46 and upper wall portion 34. It extends below hexagonally shaped flange 32. The cap 52 thus closes the upper end of the valve body, but an annular gap or space 76 exists between the inner surface of vertical side wall 58 and hexagonally shaped flange 32. The gap is in flow communication with inlet opening 40.

While two mounting posts 46 and two bolts 59 are illustrated, it is contemplated that three or four mounting posts 46 could be used, equally spaced about top edge surface 38 of annular upper sidewall 34. A bolt 59 would connect the cap 52 to each mounting post.

A modified arrangement for attachment of cap 52 is illustrated in FIG. 5. The components of the vacuum relief assembly 22 of this embodiment are essentially the same as the configuration of the embodiment of FIGS. 1-4. However, here, a flat mounting plate 49 is attached to mounting posts 46 by bolts 59. A central vertical threaded stud 50 extends upwardly of plate 49 and receives cap, 52 which includes a central hole rather than spaced holes 56 of the embodiment of FIGS. 1-4. A fastener member in the form of nut 51 secures the cap to the stud 50. The circular top wall 53 of cap 52 is modified somewhat to define an annular space to accommodate the heads of bolts 59.

In each embodiment, the vertical cylindrical side wall 58 is formed on a diameter larger than the maximum dimension of the hexagonally shaped flange 32. There is space between the cap side wall 58 and the flange 32, upper wall portion 34 and outer surfaces of mounting posts 46. Air is free to pass between the interior surface of side wall 58 into the inlet openings 40 between posts 46.

The length of side cylindrical wall 58 prohibits access to inlet opening 40 or the interior flow passage 28. It also prohibits manual depression of valve 60 against the closing force of compression spring member 69 to access the interior of containment shell 12. This relationship protects vacuum relief assembly 22 from damage and/or malicious tampering by unauthorized persons while nonetheless maintaining fluid communication between the interior passage 28 and the outside atmosphere through inlet opening 40. As shown, in the assembled condition, the sidewall 58 of the cap 68 is disposed in opposing spaced relation to the valve body 26. In this regard, the inner diameter of the cap 68 is preferably selected to provide coverage in reasonably close proximity to the exterior of the valve body 26 while nonetheless maintaining a sufficient space to maintain air flow across the separating space and into the valve cavity without substantial obstruction.

During the period of air flow, air is pulled from the atmosphere and into the spacing between the valve body 26 and the sidewall 58 of the cap 52. The air then enters the valve cavity through the open spaces 42 forming inlet opening 40. Once the pressure within the interior of the tank car has been increased to a desired level, the valve is urged back to the normal sealing condition until vacuum conditions reoccur.

Cylindrical wall 58 of cap 52 overlies the hexagonally shaped flange 32. This prohibits access to the torque acceptance configuration to thwart any effort to remove the entire vacuum relief assembly 22 from flange plate 20. Thus, a person is blocked from applying a wrench or other tool to the hexagonal flange 32 and is thereby prevented from unauthorized removal of the valve body 26 to gain access to the interior of containment shell 12.

To deter tampering by removal of cap 52, attachment bolts 59 are secured with a cable seal assembly 77. The heads of bolts 59 each include a transverse hole 78. The cable seal assembly includes a body 80 and a strand 82. One end of the strand 82 is secured to the body 80. The free end of the strand 82 is passed through the transverse holes 78 and then secured within the body 80. The bolts cannot be removed without destroying the cable seal thus providing indicia of intentional tampering. The cable seal body 80 is usually provided with a code recordable at the time of insertion to preclude substitution of a different cable seal assembly.

In the embodiment of FIG. 5, the free end of strand 82 is passed through a transverse hole in nut 51 and a transverse hole in stud 50 and secured into body 80. Since stud 50 is centrally disposed, the cap 52 is free to rotate relative to the remainder of the assembly 22 as a further deterrent to unauthorized removal.

Upon observing a broken or missing cable, the authorized user will thus be alerted to the possibility that the contents of the containment vessel may have been subjected to tampering and proper remedial measures may be taken.

Importantly, it is to be understood that the illustrated and described operational features of the valve assembly are exemplary only, and any number of other operating configurations may be utilized if desired. Accordingly, it is to be understood that the use of any and all examples, or exemplary language provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed.

No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention. Preferred embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Variations of those preferred embodiments may become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventors expect skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than as specifically described herein. 

1. A vacuum relief assembly for a containment vessel comprising: a valve body having an interior wall defining a passage including an inlet opening and an outlet opening, said outlet opening being adapted for fluid communication with a containment portion of a containment vessel and said inlet opening being open to atmosphere, a normally closed valve, closing said passage and operable to selectively open said passage between said inlet opening and said outlet opening, a cap mounted on said valve body, said cap overlying said inlet opening in spaced relation to said valve body, said cap configured to prohibit access to said passage through said inlet opening.
 2. A vacuum relief assembly as claimed in claim 1, wherein said valve body is generally cylindrical and includes a securement end portion configured to be secured to a containment vessel and wherein said cap and said valve body define a space between said valve body and said cap providing a flow path between said inlet opening and an outside atmosphere.
 3. A vacuum relief assembly as claimed in claim 2, wherein said valve body includes a generally cylindrical upper sidewall having an upper edge surface portion and at least one mounting post projecting upwardly from said upper edge surface of said sidewall portion, arcuate spaces defined by said upper edge surface and said at least one mounting post defining said inlet opening.
 4. A vacuum relief assembly as claimed in claim 3, wherein said cap is secured to said at least one mounting post.
 5. A vacuum relief assembly as claimed in claim 4 wherein said valve body includes a plurality of mounting posts projecting upward from said upper edge surface of said sidewall portion, said arcuate spaces defined by said upper edge surface and said mounting posts, and wherein said cap includes a top wall defining an interior surface supported on said mounting posts and a generally cylindrical side wall surrounding said inlet opening and said generally cylindrical upper wall portion in spaced relation thereto.
 6. A vacuum relief assembly as claimed in claim 3, wherein said valve body includes a torque acceptance configuration and said cap surrounds said torque-acceptance configuration prohibiting access thereto.
 7. A vacuum relief assembly as claimed in claim 4 wherein said valve body includes a torque-acceptance configuration and said cap surrounds said torque-acceptance configuration prohibiting access thereto.
 8. A vacuum relief assembly as claimed in claim 5 wherein said valve body includes a torque-acceptance configuration and said cap surrounds said torque-acceptance configuration prohibiting access thereto.
 9. A vacuum relief assembly as claimed in claim 6, wherein said valve body includes a shoulder surface extending radially outwardly from said valve body above said torque acceptance configuration and said generally cylindrical upper wall portion of said valve body extends upwardly from said shoulder surface.
 10. A vacuum relief assembly as claimed in claim 8, wherein said valve body includes a shoulder surface extending radially outwardly from said valve body above said torque acceptance configuration and said generally cylindrical upper wall portion of said valve body extends upwardly from said shoulder surface.
 11. A vacuum relief assembly as claimed in claim 6 wherein said torque-acceptance configuration is a hexagonally shaped flange.
 12. A vacuum relief assembly as claimed in claim 7 wherein said torque-acceptance configuration is a hexagonally shaped flange.
 13. A vacuum relief assembly as claimed in claim 8 wherein said torque-acceptance configuration is a hexagonally shaped flange.
 14. A vacuum relief assembly as claimed in claim 9 wherein said torque-acceptance configuration is a hexagonally shaped flange.
 15. A vacuum relief assembly as claimed in claim 10 wherein said torque-acceptance configuration is a hexagonally shaped flange.
 16. A vacuum relief assembly as claimed in claim 4 wherein said cap is secured to said at least one mounting post by at least one fastener member.
 17. A vacuum relief assembly as claimed in claim 7 wherein said cap is secured to said at least one mounting post by at least one fastener member.
 18. A vacuum relief assembly as claimed in claim 9 wherein said cap is secured to said at least one mounting post by at least one fastener member.
 19. A vacuum relief assembly as claimed in claim 5 wherein said cap is secured to each said mounting post by a fastener member.
 20. A vacuum relief assembly as claimed in claim 8 wherein said cap is secured to each said mounting post by a fastener member.
 21. A vacuum relief assembly as claimed in claim 10 wherein said cap is secured to each said mounting post by a fastener member.
 22. A vacuum relief assembly as claimed in claim 13 wherein said cap is secured to each said mounting post by a fastener member.
 23. A vacuum relief assembly as claimed in claim 16 wherein said at least one fastener member is secured by a cable seal assembly.
 24. A vacuum relief assembly as claimed in claim 17 wherein said at least one fastener member is secured by a cable seal assembly.
 25. A vacuum relief assembly as claimed in claim 18 wherein said at least one fastener member is secured by a cable seal assembly.
 26. A vacuum relief assembly as claimed in claim 19 wherein said fastener members are secured by a cable seal assembly.
 27. A vacuum relief assembly as claimed in claim 20 wherein said fastener members are secured by a cable seal assembly.
 28. A vacuum relief assembly as claimed in claim 21 wherein said fastener members are secured by a cable seal assembly.
 29. A vacuum relief assembly as claimed in claim 22 wherein said fastener members are secured by a cable seal assembly. 